<?php

/**
 * @file
 * Provides API for defining and handling XML-RPC requests.
 */

/**
 * Invokes XML-RPC methods on this server.
 *
 * @param array $callbacks
 *   Array of external XML-RPC method names with the callbacks they map to.
 */
function xmlrpc_server($callbacks) {
	$xmlrpc_server = new stdClass();
	// Define built-in XML-RPC method names
	$defaults = array(
			'system.multicall' => 'xmlrpc_server_multicall',
			array(
					'system.methodSignature',
					'xmlrpc_server_method_signature',
					array('array', 'string'),
					'Returns an array describing the return type and required parameters of a method.',
			),
			array(
					'system.getCapabilities',
					'xmlrpc_server_get_capabilities',
					array('struct'),
					'Returns a struct describing the XML-RPC specifications supported by this server.',
			),
			array(
					'system.listMethods',
					'xmlrpc_server_list_methods',
					array('array'),
					'Returns an array of available methods on this server.',
			),
			array(
					'system.methodHelp',
					'xmlrpc_server_method_help',
					array('string', 'string'),
					'Returns a documentation string for the specified method.',
			),
	);
	// We build an array of all method names by combining the built-ins
	// with those defined by modules implementing the _xmlrpc hook.
	// Built-in methods are overridable.
	$callbacks = array_merge($defaults, (array) $callbacks);
	drupal_alter('xmlrpc', $callbacks);
	foreach ($callbacks as $key => $callback) {
		// we could check for is_array($callback)
		if (is_int($key)) {
			$method = $callback[0];
			$xmlrpc_server->callbacks[$method] = $callback[1];
			$xmlrpc_server->signatures[$method] = $callback[2];
			$xmlrpc_server->help[$method] = $callback[3];
		}
		else {
			$xmlrpc_server->callbacks[$key] = $callback;
			$xmlrpc_server->signatures[$key] = '';
			$xmlrpc_server->help[$key] = '';
		}
	}

	$data = file_get_contents('php://input');
	if (!$data) {
		print 'XML-RPC server accepts POST requests only.';
		drupal_exit();
	}
	$xmlrpc_server->message = xmlrpc_message($data);
	if (!xmlrpc_message_parse($xmlrpc_server->message)) {
		xmlrpc_server_error(-32700, t('Parse error. Request not well formed.'));
	}
	if ($xmlrpc_server->message->messagetype != 'methodCall') {
		xmlrpc_server_error(-32600, t('Server error. Invalid XML-RPC. Request must be a methodCall.'));
	}
	if (!isset($xmlrpc_server->message->params)) {
		$xmlrpc_server->message->params = array();
	}
	xmlrpc_server_set($xmlrpc_server);
	$result = xmlrpc_server_call($xmlrpc_server, $xmlrpc_server->message->methodname, $xmlrpc_server->message->params);

	if (is_object($result) && !empty($result->is_error)) {
		xmlrpc_server_error($result);
	}
	// Encode the result
	$r = xmlrpc_value($result);
	// Create the XML
	$xml = '
	<methodResponse>
	<params>
	<param>
	<value>' . xmlrpc_value_get_xml($r) . '</value>
	</param>
	</params>
	</methodResponse>

	';
	// Send it
	xmlrpc_server_output($xml);
}

/**
 * Throws an XML-RPC error.
 *
 * @param $error
 *   An error object or integer error code.
 * @param $message
 *   (optional) The description of the error. Used only if an integer error
 *   code was passed in.
 */
function xmlrpc_server_error($error, $message = FALSE) {
	if ($message && !is_object($error)) {
		$error = xmlrpc_error($error, $message);
	}
	xmlrpc_server_output(xmlrpc_error_get_xml($error));
}

/**
 * Sends XML-RPC output to the browser.
 *
 * @param string $xml
 *   XML to send to the browser.
 */
function xmlrpc_server_output($xml) {
	$xml = '<?xml version="1.0"?>' . "\n" . $xml;
	drupal_add_http_header('Content-Length', strlen($xml));
	drupal_add_http_header('Content-Type', 'text/xml');
	echo $xml;
	drupal_exit();
}

/**
 * Stores a copy of an XML-RPC request temporarily.
 *
 * @param object $xmlrpc_server
 *   (optional) Request object created by xmlrpc_server(). Omit to leave the
 *   previous server object saved.
 *
 * @return
 *   The latest stored request.
 *
 * @see xmlrpc_server_get()
 */
function xmlrpc_server_set($xmlrpc_server = NULL) {
	static $server;
	if (!isset($server)) {
		$server = $xmlrpc_server;
	}
	return $server;
}

/**
 * Retrieves the latest stored XML-RPC request.
 *
 * @return object
 *   The stored request.
 *
 * @see xmlrpc_server_set()
 */
function xmlrpc_server_get() {
	return xmlrpc_server_set();
}

/**
 * Dispatches an XML-RPC request and any parameters to the appropriate handler.
 *
 * @param object $xmlrpc_server
 *   Object containing information about this XML-RPC server, the methods it
 *   provides, their signatures, etc.
 * @param string $methodname
 *   The external XML-RPC method name; e.g., 'system.methodHelp'.
 * @param array $args
 *   Array containing any parameters that are to be sent along with the request.
 *
 * @return
 *   The results of the call.
 */
function xmlrpc_server_call($xmlrpc_server, $methodname, $args) {
	// Make sure parameters are in an array
	if ($args && !is_array($args)) {
		$args = array($args);
	}
	// Has this method been mapped to a Drupal function by us or by modules?
	if (!isset($xmlrpc_server->callbacks[$methodname])) {
		return xmlrpc_error(-32601, t('Server error. Requested method @methodname not specified.', array("@methodname" => $xmlrpc_server->message->methodname)));
	}
	$method = $xmlrpc_server->callbacks[$methodname];
	$signature = $xmlrpc_server->signatures[$methodname];

	// If the method has a signature, validate the request against the signature
	if (is_array($signature)) {
		$ok = TRUE;
		$return_type = array_shift($signature);
		// Check the number of arguments
		if (count($args) != count($signature)) {
			return xmlrpc_error(-32602, t('Server error. Wrong number of method parameters.'));
		}
		// Check the argument types
		foreach ($signature as $key => $type) {
			$arg = $args[$key];
			switch ($type) {
				case 'int':
				case 'i4':
					if (is_array($arg) || !is_int($arg)) {
						$ok = FALSE;
					}
					break;

				case 'base64':
				case 'string':
					if (!is_string($arg)) {
						$ok = FALSE;
					}
					break;

				case 'boolean':
					if ($arg !== FALSE && $arg !== TRUE) {
						$ok = FALSE;
					}
					break;

				case 'float':
				case 'double':
					if (!is_float($arg)) {
						$ok = FALSE;
					}
					break;

				case 'date':
				case 'dateTime.iso8601':
					if (!$arg->is_date) {
						$ok = FALSE;
					}
					break;
			}
			if (!$ok) {
				return xmlrpc_error(-32602, t('Server error. Invalid method parameters.'));
			}
		}
	}

	if (!function_exists($method)) {
		return xmlrpc_error(-32601, t('Server error. Requested function @method does not exist.', array("@method" => $method)));
	}
	// Call the mapped function
	return call_user_func_array($method, $args);
}

/**
 * Dispatches multiple XML-RPC requests.
 *
 * @param array $methodcalls
 *   An array of XML-RPC requests to make. Each request is an array with the
 *   following elements:
 *   - methodName: Name of the method to invoke.
 *   - params: Parameters to pass to the method.
 *
 * @return
 *   An array of the results of each request.
 *
 * @see xmlrpc_server_call()
 */
function xmlrpc_server_multicall($methodcalls) {
	// See http://www.xmlrpc.com/discuss/msgReader$1208
	$return = array();
	$xmlrpc_server = xmlrpc_server_get();
	foreach ($methodcalls as $call) {
		$ok = TRUE;
		if (!isset($call['methodName']) || !isset($call['params'])) {
			$result = xmlrpc_error(3, t('Invalid syntax for system.multicall.'));
			$ok = FALSE;
		}
		$method = $call['methodName'];
		$params = $call['params'];
		if ($method == 'system.multicall') {
			$result = xmlrpc_error(-32600, t('Recursive calls to system.multicall are forbidden.'));
		}
		elseif ($ok) {
			$result = xmlrpc_server_call($xmlrpc_server, $method, $params);
		}
		if (is_object($result) && !empty($result->is_error)) {
			$return[] = array(
					'faultCode' => $result->code,
					'faultString' => $result->message,
			);
		}
		else {
			$return[] = array($result);
		}
	}
	return $return;
}

/**
 * Lists the methods available on this XML-RPC server.
 *
 * XML-RPC method system.listMethods maps to this function.
 *
 * @return array
 *   Array of the names of methods available on this server.
 */
function xmlrpc_server_list_methods() {
	$xmlrpc_server = xmlrpc_server_get();
	return array_keys($xmlrpc_server->callbacks);
}

/**
 * Returns a list of the capabilities of this server.
 *
 * XML-RPC method system.getCapabilities maps to this function.
 *
 * @return array
 *   Array of server capabilities.
 *
 * @see http://groups.yahoo.com/group/xml-rpc/message/2897
 */
function xmlrpc_server_get_capabilities() {
	return array(
			'xmlrpc' => array(
					'specUrl' => 'http://www.xmlrpc.com/spec',
					'specVersion' => 1,
			),
			'faults_interop' => array(
					'specUrl' => 'http://xmlrpc-epi.sourceforge.net/specs/rfc.fault_codes.php',
					'specVersion' => 20010516,
			),
			'system.multicall' => array(
					'specUrl' => 'http://www.xmlrpc.com/discuss/msgReader$1208',
					'specVersion' => 1,
			),
			'introspection' => array(
					'specUrl' => 'http://scripts.incutio.com/xmlrpc/introspection.html',
					'specVersion' => 1,
			),
	);
}

/**
 * Returns one method signature for a function.
 *
 * This is the function mapped to the XML-RPC method system.methodSignature.
 *
 * A method signature is an array of the input and output types of a method. For
 * instance, the method signature of this function is array('array', 'string'),
 * because it takes an array and returns a string.
 *
 * @param string $methodname
 *   Name of method to return a method signature for.
 *
 * @return array
 *   An array of arrays of types, each of the arrays representing one method
 *   signature of the function that $methodname maps to.
 */
function xmlrpc_server_method_signature($methodname) {
	$xmlrpc_server = xmlrpc_server_get();
	if (!isset($xmlrpc_server->callbacks[$methodname])) {
		return xmlrpc_error(-32601, t('Server error. Requested method @methodname not specified.', array("@methodname" => $methodname)));
	}
	if (!is_array($xmlrpc_server->signatures[$methodname])) {
		return xmlrpc_error(-32601, t('Server error. Requested method @methodname signature not specified.', array("@methodname" => $methodname)));
	}
	// We array of types
	$return = array();
	foreach ($xmlrpc_server->signatures[$methodname] as $type) {
		$return[] = $type;
	}
	return array($return);
}

/**
 * Returns the help for an XML-RPC method.
 *
 * XML-RPC method system.methodHelp maps to this function.
 *
 * @param string $method
 *   Name of method for which we return a help string.
 *
 * @return string
 *   Help text for $method.
 */
function xmlrpc_server_method_help($method) {
	$xmlrpc_server = xmlrpc_server_get();
	return $xmlrpc_server->help[$method];
}
